1. Field of the Invention
The present disclosure relates to a circuit board and, more particularly, to a device mounting board, which mounts a plurality of kinds of modules thereon, and a semiconductor module using said device mounting board.
2. Description of the Related Art
In recent years, along with increasing high function and high performance of LSIs (Large Scale Integrated Circuits), their power consumption is on the increase. With electronic devices getting smaller, mounting boards are also required to be smaller and high-density and multilayered (see Japanese Laid-Open Patent Applications S63-301547 and S60-072296, and International Patent Application WO 2002/014400, for instance). Accordingly, the power consumption per unit volume (heat density) of a circuit board rises. Thus the need for measures to address the increased heat radiation is increasing.
On the other hand, a semiconductor power module is used as a power conversion apparatus, which regulates the power supplied to a load, in a wide range of fields including electric appliances and industrial equipment (see Japanese Laid-Open Patent Applications H06-188363 and H06-288606, for instance). Here, the semiconductor power module is comprised of a power circuit module including a power semiconductor device (power device) and a control circuit module including a control device that controls and drives said power circuit module.
As disclosed in Japanese Laid-Open Patent Application S63-301547, the power circuit and the control circuit are fabricated as separate modules using separate substrates, and then they are contained in the same casing. In this structure as disclosed in the Related Art, it is difficult to downsize the module as a whole. On the other hand, when the power circuit and the control circuit are mounted on a metallic substrate and then this substrate is used as the ground electrode, in order to both downsize the module and improve the heat radiation property, noise generated by the power circuit sneaks around to the control circuit via the metallic substrate and this noise in turn may cause improper operations in some cases.